This invention relates to methods of measuring photo-induced voltage at the surface of semiconductor materials. More particularly, it is concerned with methods of obtaining measurements of the change in surface potential barriers in semiconductor materials using modulated monochromatic light.
It is desirable to be able to obtain measurements of the surface space-charge capacitance of bodies of semiconductor material. Information on the surface space-charge capacitance enables characterization to be made of the bulk properties and the surface properties of a semiconductor body. Although various techniques have been developed for determining the surface space-charge capacitance of semiconductor materials, they are either destructive of the body, lead to changes in the semiconductor properties in the region of the body adjacent to the surface, or are not sufficiently accurate.